GUMICS-4 analysis of interplanetary coronal mass ejection impact on Earth during low and typical Mach number solar winds

Antti Lakka*, Tuija I. Pulkkinen, Andrew P. Dimmock, Emilia Kilpua, Matti Ala-Lahti, Ilja Honkonen, Minna Palmroth, Osku Raukunen

*Corresponding author for this work

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Abstract

We study the response of the Earth's magnetosphere to fluctuating solar wind conditions during interplanetary coronal mass ejections (ICMEs) using the Grand Unified Magnetosphere-Ionosphere Coupling Simulation (GUMICS-4). The two ICME events occurred on 15-16 July 2012 and 29-30 April 2014. During the strong 2012 event, the solar wind upstream values reached up to 35 particles cm(-3), speeds of up to 694 km s(-1), and an interplanetary magnetic field of up to 22 nT, giving a Mach number of 2.3. The 2014 event was a moderate one, with the corresponding upstream values of 30 particles cm(-3), 320 km s(-1) and 10 nT, indicating a Mach number of 5.8. We examine how the Earth's space environment dynamics evolves during both ICME events from both global and local perspectives, using well-established empirical models and in situ measurements as references. We show that on the large scale, and during moderate driving, the GUMICS-4 results are in good agreement with the reference values. However, the local values, especially during high driving, show more variation: such extreme conditions do not reproduce local measurements made deep inside the magnetosphere. The same appeared to be true when the event was run with another global simulation. The cross-polar cap potential (CPCP) saturation is shown to depend on the Alfven-Mach number of the upstream solar wind. However, care must be taken in interpreting these results, as the CPCP is also sensitive to the simulation resolution.

Original languageEnglish
Pages (from-to)561-579
Number of pages19
JournalAnnales Geophysicae
Volume37
Issue number4
DOIs
Publication statusPublished - 11 Jul 2019
MoE publication typeA1 Journal article-refereed

Keywords

  • CAP POTENTIAL SATURATION
  • HIGH-LATITUDE
  • GEOMAGNETIC-ACTIVITY
  • PLASMA TRANSPORT
  • MHD SIMULATION
  • MAGNETOSPHERE
  • MODEL
  • SHOCK
  • IONOSPHERE
  • STORMS

Projects

Shocks and Magnetosheaths in the Heliosphere

Alho, M., Järvinen, R., Lakka, A., Pulkkinen, T. & Knuuttila, O.

01/09/201731/08/2022

Project: Academy of Finland: Other research funding

The turbulent magnetosheath: the impact on magnetospheric and radiation belt plasma properties

Pulkkinen, T. & Dimmock, A.

01/09/201531/05/2018

Project: Academy of Finland: Other research funding

Equipment

Science-IT

Mikko Hakala (Manager)

School of Science

Facility/equipment: Facility

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